Modelling for a game engine, stuff I should know?
Unless you tell us what game engine you're aiming for, it will be hard to be specific.

However, you shouldn't try modelling with tris, it would be hard and pointless. With triangles you can't use loops, most tools won't work as intended (ie. Bevel, Inset...) 

Either let the engine do the conversion (Unity, UE4, Godot, does it really well) ; or if you want more control, handle it yourself just before export (ie, Blender "Triangulate" modifier)